A service in recent years offers a space to change a stress level of a person in a room. As a technique for such a service, for example, a system according to Patent Document 1 is known. Upon determination of a stress level (e.g., a strain level and a fatigue level) of a person in a room, the system in Patent Document 1 automatically generates stimuli based on a result of the determination to give the person such effects as easing strain and reducing fatigue. Examples of the stimuli include refreshing sound, color, and aroma. The stimuli reduce the strain level and the fatigue level of the person.